The present invention relates to a new and improved muzzle-expellable gun cartridge.
Garland patent No. 430,229, for example, discloses a muzzle-expellable cartridge having a main charge for propelling the projectile from the cartridge case and barrel, and an auxiliary charge for expelling the case through the gun barrel after the projectile has been expelled therefrom.
An object of the invention is to provide the cartridge case with means for facilitating the forward expulsion of the case from the chamber.
In accordance with the invention, the cartridge case side wall is formed with longitudinal flutes and intermediate ribs which extend almost the full length of the side wall, and apertures in the flutes to permit propellant gases to pass through the side wall to the longitudinal spaces provided by the flutes, to collapse the side wall inwardly and thereby release it from the barrel chamber.
Czechoslovakian patent 80,541 (in 102-38) discloses a rearwardly-extracted cartridge case having openings in an annular external groove, for a similar purpose, without longitudinal flutes.